What are they? Why are they important? How are they identified?
Preview:
Citation preview
- Slide 1
- What are they? Why are they important? How are they
identified?
- Slide 2
- What are minerals? A naturally forming inorganic (non-living)
solid Crystal structure due to internal arrangement of atoms.
Specific chemical composition
- Slide 3
- Minerals are inorganic Never been alive Example: copper,
quartz, calcite. Fossils are NOT minerals- they were once living
Natural gas and oil are NOT minerals- they came from once- living
organisms
- Slide 4
- Why are minerals important? Essential natural resources If it
cant be grown it must be mined Mining is taking valuable minerals
out of the Earth.
- Slide 5
- What do we mine for? Metals- buildings, homes, plumbing,
electrical, manufacturing, transportation Rocks- buildings, roads,
manufacturing Jewelry, currency, art Health, medicine
- Slide 6
- Slide 7
- Mineral Identification Properties 1. Hardness 2. Luster 3.
Streak 4. Color 5. Cleavage 6. Fracture
- Slide 8
- Mohs Hardness Scale Hardness is the ability to scratch another
mineral Mohs uses 10 relatively common minerals to compare their
relative hardness Uses common items of known hardness to compare
with ten minerals (fingernail, steel nail, glass plate, copper
penny) Very important in mineral identification
- Slide 9
- Mohs Hardness Scale 1. Talc Softest mineral 2. Gypsum Gypsum
can scratch talc.
- Slide 10
- Mohs Hardness test A fingernail can scratch both talc(1) and
gypsum(2) A fingernail is assigned the hardness number of 2.5
- Slide 11
- 3. Calcite Calcite can scratch gypsum 4. Fluorite fluorite can
scratch calcite and softer minerals
- Slide 12
- Mohs Hardness Test A copper penny has a hardness of 3 A copper
penny can scratch minerals softer than a 3
- Slide 13
- 5. Apatite Can scratch Fluorite 6. Potassium Feldspar K-spar K
spar can scratch all softer minerals. None of the softer minerals
can scratch it.
- Slide 14
- 7. Quartz so hard it can scratch glass 8. Topaz Topaz is harder
than quartz
- Slide 15
- 9. Corundum Can scratch Topaz 10. Diamond is the hardest
natural substance known It is harder than all other minerals
- Slide 16
- Luster Quality and intensity of light reflecting off the faces
of the crystal Non-metallic Metallic
- Slide 17
- Non-metallic luster Shiny like a metal Metallic luster Dull/
Earthy Waxy, greasy or soapy Glassy Pearly Silky
- Slide 18
- Vitreous luster Glasslike Most common Ex. Quartz
- Slide 19
- Waxy Luster Has the look of wax Examples: chert,
smithsonite
- Slide 20
- Earthy/Dull Luster Non-reflective surface Dirt-like appearance
Examples: barite roses; bauxite, limonite
- Slide 21
- Pearly Luster Has the shine of a pearl Ex. Mica
- Slide 22
- Silky Luster Looks like silk Used to describe fibrous minerals,
such as asbestos
- Slide 23
- Metallic Luster Looks like shiny metal Copper, silver, gold,
platinum,
- Slide 24
- Mineral Streak The color of the powder left when a mineral is
rubbed on a streak plate The ability/inability of a mineral to
create a streak helps ID it
- Slide 25
- Mineral Streak When rubbed on a ceramic tile, some minerals
leave certain color streaks. (EX) Grey hematite leaves a red
streak
- Slide 26
- Color Color is based on what wavelength of light is absorbed
and reflected. Color is the LEAST reliable mineral ID test Many
different minerals have the same color. The same mineral can often
have different colors
- Slide 27
- ID by color Sulfur copper
- Slide 28
- Same mineral- Different colors quartz
- Slide 29
- Same Color- Different Minerals Gypsum Calcite Albite
Halite
- Slide 30
- Cleavage How a mineral breaks or splits along planes of their
crystal structure Cleaves along the same parallel plane over and
over again Occurs in minerals with specific planes of weakness
Several different types of cleaving
- Slide 31
- Octahedral cleavage Multiple cleavage planes- Fluorite
- Slide 32
- Cubic Cleavage 90 degree angles Six-sided cube Galena
Halite
- Slide 33
- Rhombohedra Cleavage Calcite
- Slide 34
- Fracture Mineral breaks along uneven lines and results in rough
and curved surfaces. Conchoidal Fracture- looks like a clam shell.
Due to atomic configuration.
- Slide 35
- Other Properties used to ID minerals Magnetism Acid test
calcium bubbles when touched with an acid: calcite Fluorescence
glow under UV light Salty- contain naturally occurring salt:
(halite)